From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E8C5CA9EC5 for ; Wed, 30 Oct 2019 13:41:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C03B20578 for ; Wed, 30 Oct 2019 13:41:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726622AbfJ3NlM (ORCPT ); Wed, 30 Oct 2019 09:41:12 -0400 Received: from mga04.intel.com ([192.55.52.120]:45426 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726222AbfJ3NlL (ORCPT ); Wed, 30 Oct 2019 09:41:11 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Oct 2019 06:41:11 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,247,1569308400"; d="scan'208";a="283555445" Received: from um.fi.intel.com (HELO um) ([10.237.72.57]) by orsmga001.jf.intel.com with ESMTP; 30 Oct 2019 06:41:05 -0700 From: Alexander Shishkin To: Peter Zijlstra , "Kang\, Luwei" Cc: "kvm\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" , "pbonzini\@redhat.com" , "rkrcmar\@redhat.com" , "Christopherson\, Sean J" , "vkuznets\@redhat.com" , "wanpengli\@tencent.com" , "jmattson\@google.com" , "joro\@8bytes.org" , "tglx\@linutronix.de" , "mingo\@redhat.com" , "bp\@alien8.de" , "hpa\@zytor.com" , "x86\@kernel.org" , "ak\@linux.intel.com" , "thomas.lendacky\@amd.com" , "acme\@kernel.org" , "mark.rutland\@arm.com" , "jolsa\@redhat.com" , "namhyung\@kernel.org" , alexander.shishkin@linux.intel.com Subject: Re: [PATCH v1 3/8] KVM: x86: Allocate performance counter for PEBS event In-Reply-To: <20191030094941.GQ4097@hirez.programming.kicks-ass.net> References: <1572217877-26484-1-git-send-email-luwei.kang@intel.com> <1572217877-26484-4-git-send-email-luwei.kang@intel.com> <20191029144612.GK4097@hirez.programming.kicks-ass.net> <82D7661F83C1A047AF7DC287873BF1E173835B1A@SHSMSX104.ccr.corp.intel.com> <20191030094941.GQ4097@hirez.programming.kicks-ass.net> Date: Wed, 30 Oct 2019 15:41:04 +0200 Message-ID: <87k18mfj0v.fsf@ashishki-desk.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra writes: > On Wed, Oct 30, 2019 at 04:06:36AM +0000, Kang, Luwei wrote: >> > > static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type, >> > > unsigned config, bool exclude_user, >> > > bool exclude_kernel, bool intr, >> > > - bool in_tx, bool in_tx_cp) >> > > + bool in_tx, bool in_tx_cp, bool pebs) >> > > { >> > > struct perf_event *event; >> > > struct perf_event_attr attr = { >> > > @@ -111,9 +111,12 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type, >> > > .exclude_user = exclude_user, >> > > .exclude_kernel = exclude_kernel, >> > > .config = config, >> > > + .precise_ip = pebs ? 1 : 0, >> > > + .aux_output = pebs ? 1 : 0, >> > >> > srsly? >> >> Hi Peter, >> Thanks for review. For aux_output, I think it should be set 1 when the guest wants to enabled PEBS by Intel PT. >> For precise_ip, it is the precise level in perf and set by perf command line in KVM guest, this may not reflect the accurate value (can be 0~3) here. Here set to 1 is used to allocate a counter for PEBS event and set the MSR_IA32_PEBS_ENABLE register. For PMU virtualization, KVM will trap the guest's write operation to PMU registers and allocate/free event counter from host if a counter enable/disable in guest. We can't always deduce the exact parameter of perf command line from the value of the guest writers to the register. > > Please, teach your MUA to wrap on 78 chars. > > The thing I really fell over is the gratuitous 'bool ? 1 : 0'. But yes, Notice the .exclude_kernel assignment above that does the same thing the other way around. Regards, -- Alex